What is an EV?

'EV', a term gaining increasing popularity in the motoring world, stands for Electric Vehicle. Although there are already almost 200,000 EVs on UK roads - a figure expected to top one million by 2021 - most UK drivers know little about EVs or why their next car may be electric.

This guide therefore aims to answer some of the key questions about EVs: what they are, how they work, their advantages and disadvantages, their suitability for different journeys, what models are available and the methods of EV charging.

Essentially, an EV is a car or van that is powered by an electric motor, the energy being stored in a large on-board battery, which is capable of driving in electric-only mode for a reasonable range, typically at least 20 miles.

The majority of EVs are therefore 'plug-in vehicles', the battery being able to be charged from an external energy source via a plug. For this reason, the terms 'plug-in vehicles' and 'electric vehicles' are used interchangeably.

While the purest type of EV is 100% powered by electricity at all times, there are other types of electric vehicle, each of which offer distinct advantages and are more suited for particular types of driving.

What are the EV options?

Things are never quite as simple as they first appear. There are four possible types of EV, each having a different configuration of battery, motor and, in some cases, small conventional engine.

Pure-electric vehicles, the most fundamental type of EV, are propelled solely by an electric motor which gets its energy from a rechargeable battery. Also known as a battery-electric vehicle (BEV), this EV-type has the simplest set-up. As pure-EVs are powered by the electric motor at all times, there are no tailpipe-emissions (or exhaust pipe for that matter), which is good for the environment and can significantly reduce your car running costs.

A key issue for BEVs is the distance they can drive on a full charge. While ranges vary widely depending on the model, most small, city-EVs have a range of 80-100 miles in real-world driving and the latest family-sized EVs can comfortably cover 150-200 miles. Many premium electric models offer ranges of at least 250 miles, with a few able to cover more than 300 miles before needing to be recharged.

The second main EV-type is a Plug-in Hybrid EV (or PHEV) which combines an electric power-train with a small conventional engine. Combining the 'best of both worlds', PHEVs are capable of operating in electric-only mode (typically for 20-50 miles) but without the range limitations of pure-EVs. Although their zero-emission range is less than for pure-electrics, PHEVs are highly versatile which accounts for them being the most popular type of EV in the UK.

PHEVs can operate in at least three modes: using just the electric motor, just the conventional engine, or a combination of the two, with each model having a different set-up. What they have in common, however, is that once the battery's charge is depleted, or held for a later section of the journey, the engine takes over and powers the vehicle on conventional fuel.

While far fewer in number, the other two EV types are range-extended and fuel cell EVs (FCEVs). The former sees a very small engine act as an on-board generator; this never drives the wheels, but can top up the battery's charge on the go, typically doubling the available range. FCEVs are fuelled by hydrogen that, using a fuel cell, generates electricity on-demand which is then converted to motion using electric motors as with other EVs.

Range-extended electrics combine many of the benefits of BEVs and PHEVs, but are relatively rare, with most car makers opting instead to develop pure-EVs or plug-in hybrids. While the biggest bonus of FCEVs is that it takes only a few minutes to refuel, finding a hydrogen station is a bit more of a problem as there are only a handful in the UK.

How do you charge an EV?

If you are considering buying or using an EV, you are bound to have questions about charging including: Where can I charge? How long does it take? And of course, what will it cost?

The first thing to know is that most pure-EVs are 'slow' charged at home overnight, which means the vehicle is ready with a full battery each morning. Although this takes 6-8 hours for most models, home charging makes sense for several reasons: the car's parked all night anyway, electricity is usually cheapest off-peak, plus the grid is generally greenest at night when overall demand is low. You may be interested to know that Scottish Power now offers a tariff specifically designed for EV drivers to charge at home.

However, home-charging does require having access to private parking where you can locate and use your own charge point. A second popular option therefore is to charge at work, which again makes good sense as the car is not doing much. An increasing number of businesses are installing charge points for their employees and to attract visitors or customers.

Fortunately, for EV users without access to a home or workplace charge point, there is a growing network of high-power public EV chargers across the UK. With 10,000 devices already installed and 300 being added every month, using the public network is increasingly handy and often essential, particularly when on longer journeys beyond an EV's driving range.

Most public chargers are classed as 'fast' (typically 7 kW) or rapid (50 kW or more) with fast chargers being installed in shopping centre and retail car parks, or at popular destinations such as hotels and tourist sites. A fast charger will typically top-up an EV with an additional 20 miles per hour of charging. Not a full charge solution, but a useful way to extend your range.

For longer trips, rapid charging is essential for pure-EV use and that is why there are almost 2,000 rapid units now sited at motorway services and other main cross-country routes. The most common rapid chargers add 150 miles per hour of charging and will fully charge a standard EV in around 40 minutes, just enough time to enjoy a coffee during a break from driving.

Of course, PHEV users are less dependent on charging whether at home or on the public network, but will get fewer miles on electric due to their lower battery size. This also impacts on fuel costs, which for pure-EVs can be as low as 3-4 p/mile when charging at home, typically saving around 10 p/mile as compared to conventional car, while a plug-in hybrid running on electric 50% of the time will see only half that benefit.

While most EV owners will tell you that home charging is simple and reliable and that the public network is improving, it is true to say that using an EV does require getting used to new driving routines (such as plugging in the car when you get home or to work) and a degree of planning before setting out on longer journeys. That said, they will also tell you that once you have driven an EV, you will never want to drive anything else.